Gas tube energizing and timing device



e 1953 s. c. ROCKAFELLOW GAS TUBE ENERGIZING AND TIMING DEVICE FiledFeb. 3, 1951 IN VEN TOR.

f M ORNEV STUART C. POCKAFELLOW Patented Feb. 10, 1953 GAS TUBEENERGIZING AND TIMING DEVICE Stuart 0. Rockafellow, Farmington, Mich.,as-

signor to Robotron Corporation, Detroit, Mich., a corporation ofMichigan Application February 3, 1951, Serial No. 209,281

7 Claims.

This invention relates to means for momentarily energizing a gas filledphotoflash bulb and, more particularly, it relates to means forenergizing same by which the photoflash bulb may be separated by aconsiderable distance from the power source and the connection theretomade with only two wires, which wires may carry current at a relativelymoderate potential. Further, this invention relates to a device whereinthe control of the energization of said photofiash tube may be eifectedeither manually or automatically.

In the present type of systems using the newer kinds of gas filledphotoflash bulbs, such as that sold by the General Electric Companyunder the trade designation of FT 110, and further illustrated by U. S.Patent No. 2,399,222, a voltage of around 1,000 volts is placed acrosselectrodes located at opposite ends of said bulbs. A starter electrodeis wound around the tube and when a high voltage, such as 10,000 volts,is placed between the starting electrode and one of the main electrodesa spark jumps between the starting electrode and one of the mainelectrodes. This spark initiates ionization of the gas within the tubeand this permits a flow of current between the said electrodes whichcurrent is usually stored in high capacity condensers. The large flowbetween the two main electrodes drains the condensers, and a current ofshort duration and high value causes such multiple ionization of the gasin the tube to create light of very great intensity. In said presentsystems, the high voltage for the starting electrode is usuallydeveloped by small pulsing transformers of a well known type andparticularly such as are commonly used with model gas engines. Theprimary winding of this transformer is energized from the voltage acrossthe condensers.

This circuit, however, requires three conductors going to the flashbulb. This is not only inconvenient and relatively expensive in itsrequirement for wire where the flash bulb is to be placed a substantialdistance from the source of potential, but it also requires relativelyheavy insulation of said wires in order to control the high potentialsbeing conducted thereby.

In the present method, however, it is possible to locate the smallpulsing transformer adjacent the fiash bulb and only two wires are thennecessary between the charged condensers and the pars immediatelyassociated with the flash bulb. This eliminates the difficulty mentionedin the preceding paragraph and makes it feasible to use the tube atsubstantial distances from its source of energy.

It thus becomes feasible to use this type of flash bulb as a signalingdevice having use as a distress signal for boats in open water or foraircraft subjected to forced landings.

For signaling purposes, it is desirable that the apparatus be controlledmanually, if desired, and otherwise that it be capable of efiectingautomatic repeated fiashings on an automatic control.

Accordingly, a principal object of the invention is to provide effectiveand simple means for energizing gas filled photoflash bulbs forextremely short periods of time.

A further object of the invention is to provide means, as aforesaid,which is relatively simple and of small volume and weight.

A further object of the invention is to provide apparatus, as aforesaid,comprised of parts of such physical size and arrangement that thephotoflash bulb and any parts necessarily associated adjacent theretocanieasibly be spaced a substantial distance from the rest of theapparatus and be connected thereto by only two wires.

A further object of the invention is to provide apparatus, as aforesaid,wherein said wires carry at a relatively moderate potential and therebyeliminate the necessity of providing heavy insulation on said wires.

A further object of the invention is to provide apparatus, as aforesaidwhich may be readily converted from manual to automatic control and viceversa.

A further object of the invention is to provide apparatus, as aforesaid,having therein no movable parts, excepting a relay, and being of a highdegree of accuracy and reliability.

Qther objects and purposes of the invention will become apparent topersons acquainted with this kind of apparatus upon examination of thefollowing specification and inspection of the accompanying drawing.

In the drawing there is shown a circuit diagram embodying andillustrating the invention.

General construction In general, the circuit comprises a voltagedoubling circuit with its output terminals connected in series to apulse controlling capacitor and to the primary winding of a pulsingtransformer. The secondary winding of said pulsing transformer isconnected to the starting electrode and to one of the main electrodes ofthe photoflash tube. One output terminal of said voltage doublingcircuit is also connected directly to said one main electrode. The othermain electrode of the photofiash tube is connected between saidcapacitor and the other terminal of the voltage doubling circuit. Thewinding of a relay solenoid, and a capacitor in parallel therewith, areinterposed in series into the circuit between the transformer secondarywinding and one of the main condensers in the voltage doubling circuit.The normally closed contacts of said relay are connected in series withsaid other terminal of the voltage doubling circuit and the pulsecontrolling capacitor. As the main condensers are charged, currentpasses through said relay winding and holds said relay open. As soon assaid condensers become charged, the current ceases to pass through saidwinding, so that the winding becomes de-energized and the relay contactsare allowed '50 close, thus closing the circuit through the pulsecontrolling capacitor and the pulsing transformer and thereby effectingthe imposition of a high potential of short duration onto the photofiashbulb.

Detailed description Turning now to the diagram and describing thecircuit in more detail, the primary winding I or a power transformer 2may be supplied by any convenient source of alternating current, such asa hand or power driven generator or a battery energized vibrator supply.By a suitable step-up ratio the secondary winding 3 of said transformeris caused to provide a voltage output of the order of 500 to 1,000volts. Any conventional voltage doubling circuit may be used to build upa charge across the main, or power, capacitors 8 and 9. In thisparticular instance, a first end 32 of the secondary winding 3 isconnected through a rectifier 4 to one end of the relay winding 6. Acapacitor l of suitable capacity i connected in parallel with saidwinding. A variable resistor 23 is also connected in parallel with saidwinding 6. The other end of said winding is connected to one side of thepower capacitor 8 and the other side of said capacitor 8 is connected tothe other end3l of said secondary winding 3. Said other end 3| of saidsecondary winding is also connected through the point 30 to one side ofthe power capacitor 9 and the other side of said capacitor is connectedthrough the rectifier 5 to the first end 32 of said secondary windingS.

The voltages across the power capacitors 8 and 9 being additive, thetotal voltage across both capacitors is equal to about double thevoltage across the secondary winding 3. The respective capacities of thecapacitors 8 and 9 willgovern the amount of current passing through thephotofiash bulb and thus will determine the intensity of the flash.

A point 33 located between the capacitor 8 and the relay winding 6constitutes one output terminal for the voltage doubling circuit and isconnected to the main electrode [9 of the photoflash tube l8. Saidoutput terminal is also connected to one end of the primary winding l5of a small pulsing transformer l6, said transformer having such ratio asneeded to provide on its secondary winding I? the voltage needed tostart the photofiash tube [8, such as 10,000 volts. The other end ofsaid primary winding is connected to one side or" the pulse controllingcapacitor 13 and the other side of the said capacitor i connectedthrough the manual switch 12 and the pole 36 of the two-pole selectorswitch E0 to the point 35, constituting the other output terminal of thevoltage doubling circuit, which point is located between the powercapacitor 9 and the rectifier 5.

The contacts ll of the relay are normally closed and are located betweenthe other pole 3'! of said selector switch it) and the capacitor IS. Thelocation relative to each other of the primary winding I5, the capacitorl3 and the group comprising said switches and the relay contacts as heregiven is illustrative only for they may be placed in any order in the D.C. circuit energized by the power capacitors, provided only they remainin series circuit.

A relatively high resistance M is connected in parallel with thecapacitor 3 for the purpose of discharging same between periods ofoperation. The value of said resistance will be chosen to effect saiddischarge within the shortest period of time desired between operations.

'lhe starting electrode ill of the photoflash tube 50 is connected toone end of the secondary winding H of the said pulsing transformer andthe other end of said secondary winding i connected to the mainelectrode E9 of said photoflash tube. The other main electrode 20 ofsaid photoflash tube is connected, as at the point 38, into the circuitbetween the capacitor 13 and the switches H and E2.

The part of the circuit from point 34 through winding :5, throughcapacitor i3 including the resistor It, the switches and back to point35 will sometimes be referred to as the pulse circuit and the part ofthe circuit including secondary l! and the photofiash tube willsometimes be referred to as the energizing circuit. The voltage doublingcircuit, including the relay winding 5 and the capacitor 1 mayalternatively be called the power circuit.

Operation With the switch [0 engaging contact 36, the unit will bemanually operated.

In its at rest position, alternate energization of the secondary winding3 will act through the rectifiers d and 5 to charge the capacitors 8 and9 to the limit of their respective capacities. Then, upon closing thepush button switch l2, the capacitor I3 will be charged immediately.This will effect the flow of a large number of electrons, that is, willeffect a strong but brief surge of current, through the primary windingl5 of the pulsing transformer 16. With this large flow of currentthrough said primary winding I5, a voltage of a high order, as about10,000 volts, is efiected in aid secondary winding [1 and imposedbetween the starting electrode 2| and the main electrode i9. Thisvoltage is great enough to cause a spark to jump the gap between saidelectrodes l9 and 2! and thereby start ionization of the gas within thephotoflash tube and thereby allow the full current from the capacitors 3and 9 to now between the main electrodes l9 and 20. This will cause avery brilliant light of duration measured by the period of time requiredby capacitors 8 and 9 to discharge to a potential below which lightisnot created. This period will normally be measured in microseconds, suchas approximately 200 microseconds.

In the meantime, the charge on the capacitor is is draining out throughthe resistor 14 so that by the time the apparatus is'ready to initiateanother hash of light, the capacitor I3 is substantially discharged andready to repeat the operation above described.

For automatic repetitive operation, the selector switch It is placed incontact with'the terminal 31 in the pulse circuit. With the capacitors 8and 9 both discharged, when current first starts flowing from thesecondary winding 3 of the transformer 2 it will flow through the relaywinding 6 and thereby energize same and cause it to hold open thenormally closed relay contacts H. The capacitor i will hold said windingenergized dur ing the otherwise inactive half cycles. However, when thecapacitor 8 becomes fully charged, or substantially so, the flow ofelectrons through the relay winding 8 diminishes to a sufllciently lowvalue that said winding becomes de-energized and the contacts l 5 close.This, then, effects the same sequence of operations above described asoccurring when the push button switch I2 is closed and thereby causesthe flash bulb to become energized.

As soon as the flow through the flash blub l8 dicsharges the capacitors8 and 9, they will again begin drawing charge from the secondary winding3 of the transformer 2, the relay winding 6 is again energized and thecontacts II are again opened. It will be appreciated that this processwill be automatically repetitive for so long as a source of energy isprovided to the primary winding I of the transformer 2.

The frequency at which the photofiash tube [8 will become illuminatedwill depend upon the resistance value of the relay coil 6, the value ofthe capacitor 7 and upon the selected value of the variable resistor 23.Said values may be readily chosen according to conventional practice todetermine the frequencies desired.

One particular use contemplated for this circuit, which is illustrativeof its uitility but by no means limiting, contemplates placing thephototube 18 along with the pulsing transformer I6 and capacitor [3 andresistor M in suitable means to be released with a balloon from aircraftwhich has been subject to a forced landing. The rest of the apparatusremains on the ground for operation by any convenient means, such as ahand generator. The conductors 40 and 4| connect the ground apparatus tothe apparatus which is aloft and do so by only two wires havingrelatively moderate potentials therein.

Thus, either an automatically or a manually flashing light of greatintensity may be held aloft a substantial distance above said groundedaircraft and the work of search parties thereby greatly facilitated.When so used as a signal device to be carried aloft, it is apparent thatthe pulsing transformer I6, the pulse controlling capacitor l3 and theresistance M will all be associated closely together and in closeproximity to the photofiash tube I8. Thus, means will be provided bywhich said parts are held in closely compact relationship so as to bereadily lifted by said balloon. The broken line 45 indicates anyconventional means for holding said parts in such manner.

Likewise, the parts comprising the transformer 2, the power capacitors 8and 9, the relay and the manual control switch [2, together with theconductors and other parts associated therewith will normally beenclosed in .a suitable box and arranged in closely assembledrelationship with each other. The broken line 46 represents anyconventional container suitable for this purpose. The conductors 40 and4| may, in the light of the foregoing, obviously be of very great lengthand there-by permit the photofiash device and the means contained withinthe box 45 to be separated a substantial distance from the rest of theapparatus.

Alternatively, the light may be placed in a lighthouse, on a. pole, onan airfield tower, or the whole apparatus may be consolidated intoafsingle box where there is. no need to have the light spaced anymaterial distance from the power source.

While the foregoing specification and accompany drawing illustrate anddescribe one specific embodiment of the invention, it will be apparentto those familiar with apparatus of this sort that several variationsand changes in addition to those above specifically mentioned may bemade therein without taking the invention'out of the scope of thehereinafter appended claims except as said claims may expressly requireotherwise.

I claim:

1. In an energization and timing device for a photofiash tube, thecombination comprising: a source of alternating potential; meansproviding a voltage doubling. circuit including a pair of powercapacitors in series with each other and a relay winding in series withone of said capacitors; a capacitor in parallel with said relay-winding;a pulsing transformer having primary and secondary windings; a relay; apulse controlling capacitor; means connecting said pulse controllingcapacitor and the primary winding of said pulsing transformer in serieswith each other and in series with said power capacitors, said meansincluding the contacts of said relay; means connecting one end of thesecondary winding of said pulsing transformer to one of the principalelectrodes of the photofiash tube and means connecting the other end ofsaid secondary winding to the starting electrode of said photofiashtube; and means connecting said one principal electrode also to one sideof one of said power capacitors and means connecting the other of theprincipal electrodes of the photofiash tubes to the opposite side of theother of said power capacitors.

2. A device defined in claim 1 having also a resistor bridging saidpulse capacitor.

3. An apparatus defined in claim 1 having a two pole, selector switch inseries with the contacts of said relay and adjacent thereto, said relaycircuit being connected to one of said two poles, and having a manuallyoperated switch connected to the other of said poles and bridging saidrelay.

4. In an energization and timing device having a photofiash tube, saidphotofiash tube having a pair of principal electrodes and a startingelectrode, the combination comprising: a source of alternatingpotential; means providing a voltage doubling circuit connected to saidsource, said means including a pair of power capacitors in series witheach other and having a pair of output terminals located one on eachside of the respectively remote sides of said pair of power capacitors;a relay having contacts and a relay winding, said relay winding beinginterposed into said voltage doubling circuit in series with one of saidpower capacitors, and a relay capacitor connected in parallel with saidrelay winding; a pair of conductors connecting said terminals with theprincipal electrodes of said photofiash tube, the contacts of said relaybeing interposed into the circuit of one of said conductors, a pulsetransformer and a pulse controlling capacitor and means connecting theprimary winding of said pulse transformer and said pulse controllingcapacitor in series with each other and between said conductors; meansconnecting the secondary Winding of said pulse transformer between oneof said principal electrodes and said tarting electrode.

5. Apparatus defined .in .claim 4 having a ;re-

sistor bridging said pulse controlling capacitor.

'6. In apparatus :for aenergizing a load of high initial resistance andlow resistance after initial resistance has been overcome, thecombination comprising: a source of alternating potential; a powercapacitor and means including alrectifier connecting each side of saidcapacitor to said source; a second power capacitor andmeans connectingone side thereof to a point between said first power capacitor and theside 'of said source connected thereto, and means including a rectifierconnecting the other side of said second power capacitor to the otherside of said source, said rectifier being of opposite polarity withrespect to said first named rectifier; a relay having contacts and awinding; said winding .being included in series between one of saidpower capacitors and said source; a pair of terminal points located onrespectively opposite sides of said power capacitors; and a pair ofconductors connecting said terminals to said load; the contacts of saidrelay being normally closed and being interposed into the circuit of oneof said conductors.

7. In a signaling device including a photoflash tube having principalelectrodes and a starting electrode, the combination defined in claim 6together with: a pulsing transformer,

having primary and secondary windings, and a pulse controllingcapacitor; mean connecting the primary winding of said transformer andsaid pulse controlling capacitor in series with each other and betweensaid two conductors, means connecting said two conductors to theprincipal electrodes of said photofiash tube and means connecting thesecondary winding of said pulse transformer between one of said mainelectrodes and said starting electrode, said pulse transformer and saidcapacitor being mounted in close proximity to said photofiash tube, andsaid relay, said power capacitors, and the means associated directlytherewith, being mounted in close proximity with said source; wherebysaid photoflash tube may be separated by a substantial distance fromsaid power capacitors and said relay.

STUART C. vROCKAFELLOW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,275,635 Lindenblad Mar. 10,1942 2,498,640 Beck Feb. 28, 1950 2,513,396 Beck July 4, 1950

